Biocompatible hydrogel capsules and process for preparing same

Abstract

Described herein are compositions and methods for preparing hydrogel capsules using a cross-linking solution comprising a process additive. The process additive improves the quality of the resulting hydrogel capsules, such as increasing the number of defect-free capsules.

The invention claimed is: 
     
       1. A process for preparing a hydrogel capsule composition from an alginate polymer solution,
 wherein the alginate polymer solution comprises an afibrotic hydrogel-forming alginate polymer and an unmodified hydrogel-forming alginate polymer, 
 wherein the process comprises contacting a plurality of droplets of the alginate polymer solution with an aqueous cross-linking solution for a period of time sufficient to produce hydrogel capsules, 
 wherein the cross-linking solution comprises a cross-linking agent comprising a divalent cation, a buffer, an osmolarity-adjusting agent and a surfactant, 
 wherein the surfactant is a poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) PEO-PPO-PEO) triblock copolymer; and 
 wherein the alginate polymer solution further comprises a cell suspension comprising a plurality of cells. 
 
     
     
       2. The process of  claim 1 , wherein the surfactant reduces the surface tension of the cross-linking solution by about 1%, or more. 
     
     
       3. The process of  claim 1 , wherein at least 95% of the hydrogel capsules prepared are spherical capsules. 
     
     
       4. The process of  claim 1 , wherein the surfactant is selected from the group consisting of: poloxamer 188, and poloxamer 407. 
     
     
       5. The process of  claim 1 , wherein the cross-linking agent is selected from the group consisting of:
 a) BaCl 2  at a concentration of 1 mM to 100 mM; 
 b) CaCl 2  at a concentration of 50 mM to 100 mM; 
 c) SrCl 2  at a concentration of 37.5 mM to 100 mM; 
 d) a mixture of BaCl 2  at a concentration of 5 mM to 20 mM and CaCl 2  at a concentration of 37.5 mM to 12.5 mM; and 
 e) a mixture of BaCl 2  at a concentration of 5 mM to 20 mM and SrCl 2  at a concentration of 37.5 mM to 12.5 mM. 
 
     
     
       6. The process of  claim 5 , wherein the surfactant is poloxamer 188 and the cross-linking agent is BaCl 2  at a concentration of 1 mM to 100 mM. 
     
     
       7. The process of  claim 6 , wherein the cross-linking solution comprises 25 mM HEPES buffer, 20 mM BaCl 2 , 0.2M mannitol and poloxamer 188. 
     
     
       8. The process of  claim 5 , wherein the cross-linking agent is SrCl 2  at a concentration of 37.5 mM to 100 mM. 
     
     
       9. The process of  claim 8 , wherein the cross-linking solution comprises 50 mM strontium chloride hexahydrate, 0.165 M mannitol, and 25 mM HEPES. 
     
     
       10. The process of  claim 1 , wherein the afibrotic hydrogel-forming polymer comprises a compound of Formula (I): 
       
         
           
           
               
               
           
         
       
       or a salt thereof, wherein:
 A is alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, —O—, —C(O)O—, —C(O)—, —OC(O)—, —N(R C )—, —N(R C )C(O)—, —C(O)N(R C )—, —N(R C )C(O)(C 1 -C 6 -alkylene)-, —N(R C )C(O)(C 1 -C 6 -alkenylene)-, —N(R C )N(R D )—, —NCN—, —C(═N(R C )(R D ))O—, —S—, —S(O) x —, —OS(O) x —, —N(R C )S(O) x , —S(O) x N(R C )—, —P(R F ) y —, —Si(OR A ) 2 —, —Si(R G )(OR A )—, —B(OR A )—, or a metal, each of which is optionally linked to an attachment group and is optionally substituted by one or more R 1 ; 
 each of L 1  and L 3  is independently a bond, alkyl, or heteroalkyl, wherein each alkyl and heteroalkyl is optionally substituted by one or more R 2 ; 
 L 2  is a bond; 
 M is absent, alkyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl, each of which is optionally substituted by one or more R 3 ; 
 P is absent, cycloalkyl, heterocycyl, or heteroaryl, each of which is optionally substituted by one or more R 4 ; 
 Z is hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, —OR A , —C(O)R A , —C(O)OR A , —C(O)N(R C )(R D ), —N(R C )C(O)R A , cycloalkyl, heterocyclyl, aryl, or heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is optionally substituted by one or more R 5 ; 
 each R A , R B , R C , R D , R E , R F , and R G  is independently hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, halogen, azido, cycloalkyl, heterocyclyl, aryl, or heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is optionally substituted with one or more R 6 ; 
 or R C  and R D , taken together with the nitrogen atom to which they are attached, form a ring, optionally substituted with one or more R 6 ; 
 each R 1 , R 2 , R 3 , R 4 , R 5 , and R 6  is independently alkyl, alkenyl, alkynyl, heteroalkyl, halogen, cyano, azido, oxo, —OR A1 , —C(O)OR A1 , —C(O)R B1 , —OC(O)R B1 , —N(R C1 )(R D1 ), —N(R C1 )C(O)R B1 , —C(O)N(R C1 ), SR E1 , S(O) x R E1 , —OS(O) x R E1 , —N(R C1 )S(O) x R E1 , —S(O) x N(R C1 )(R D1 ), —P(R F1 ) y , cycloalkyl, heterocyclyl, aryl, heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is optionally substituted by one or more R 7 ; 
 each R A1 , R B1 , R C1 , R D1 , R E1 , and R F1  is independently hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl is optionally substituted by one or more R 7 ; 
 each R 7  is independently alkyl, alkenyl, alkynyl, heteroalkyl, halogen, cyano, oxo, hydroxyl, cycloalkyl, or heterocyclyl; 
 x is 1 or 2; and 
 y is 2, 3, or 4. 
 
     
     
       11. The process of  claim 10 , wherein the compound of Formula (I) is a compound of (II) 
       
         
           
           
               
               
           
         
       
       or a salt thereof, wherein Ring M 1  is cycloalkyl, heterocyclyl, aryl, or heteroaryl, each of which is optionally substituted with 1-5 R 3 ; Ring Z 1  is cycloalkyl, heterocyclyl, aryl or heteroaryl, optionally substituted with 1-5 R 5 ; each of R 2a , R 2b , R 2c , and R 2d  is independently hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, halo, cyano, nitro, amino, cycloalkyl, heterocyclyl, aryl, or heteroaryl, or each of R 2a  and R 2b  or R 2c  and R 2d  is taken together to form an oxo group; X is O or absent, N(R 10 )(R 11 ) O, or S; R C  is hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl, wherein each of alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with 1-6 R 6 ; each R 3 , R 5 , and R 6  is independently alkyl, alkenyl, alkynyl, heteroalkyl, halogen, cyano, azido, oxo, —OR A1 , —C(O)OR A1 , —C(O)R B1 , —OC(O)R B1 , —N(R C1 )(R D1 ), —N(R C1 )C(O)R B1 , —C(O)N(R C1 ), SR E1 , cycloalkyl, heterocyclyl, aryl, or heteroaryl; each of R 10  and R 11  is independently hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, —C(O)OR A1 , —C(O)R B1 , —OC(O)R B1 , —C(O)N(R C1 ), cycloalkyl, heterocyclyl, aryl, or heteroaryl; each R A1 , R B1 , R C1 , R D1 , and R E1  is independently hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, wherein each of alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl is optionally substituted with 1-6 R 7 ; each R 7  is independently alkyl, alkenyl, alkynyl, heteroalkyl, halogen, cyano, oxo, hydroxyl, cycloalkyl, or heterocyclyl; each m and n is independently 1, 2, 3, 4, 5, or 6; and “ ” refers to a connection to an attachment group or the hydrogel-forming polymer. 
     
     
       12. The process of  claim 10 , wherein the compound of Formula (I) is a compound of Formula (III): 
       
         
           
           
               
               
           
         
       
       or a salt thereof, wherein M is a alkyl or aryl, each of which is optionally substituted with one or more R 3 ; L 3  is alkyl or heteroalkyl optionally substituted with one or more R 2 ; Z is alkyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl, each of which is optionally substituted with one or more R 5 ; each of R 2a  and R 2b  is independently hydrogen, alkyl, or heteroalkyl, or R 2a  and R 2b  is taken together to form an oxo group; each R 2 , R 3 , and R 5  is independently alkyl, heteroalkyl, halogen, oxo, —OR A1 , —C(O)OR A1 , or —C(O)R B1 ; each R A1  and R B1  is independently hydrogen, alkyl, or heteroalkyl; n is independently 1, 2, 3, 4, 5, or 6; and “ ” refers to a connection to an attachment group or the hydrogel-forming polymer. 
     
     
       13. The process of  claim 10 , wherein the compound of Formula (I) is a compound of Formula (IV): 
       
         
           
           
               
               
           
         
       
       or a salt thereof, wherein Z 1  is alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl, each of which is optionally substituted with 1-5 R 5 ; each of R 2a , R 2b , R 2c , and R 2d  is independently hydrogen, alkyl, alkenyl, alkynyl, heteroalkyl, halo, cyano, nitro, amino, cycloalkyl, heterocyclyl, aryl, or heteroaryl; or R 2a  and R 2b  or R 2c  and R 2d  are taken together to form an oxo group; R C  is hydrogen, alkyl, alkenyl, wherein each of alkyl and alkenyl is optionally substituted with 1-6 R 6 ; each of R 3 , R 5 , and R 6  is independently alkyl, heteroalkyl, halogen, oxo, —OR A1 , —C(O)OR A1 , or —C(O)R B1 ; each R A1  and R B1  is independently hydrogen, alkyl, or heteroalkyl; m and n are each independently 1, 2, 3, 4, 5, or 6; q is an integer from 0 to 25; and “ ” refers to a connection to an attachment group or the hydrogel-forming polymer. 
     
     
       14. A process for preparing a hydrogel capsule composition from an alginate polymer solution,
 wherein the alginate polymer solution comprises an afibrotic hydrogel-forming alginate polymer and an unmodified hydrogel-forming alginate polymer, 
 wherein the process comprises contacting a plurality of droplets of the alginate polymer solution with an aqueous cross-linking solution for a period of time sufficient to produce hydrogel capsules, 
 wherein the cross-linking solution comprises BaCl 2 , HEPES buffer, mannitol, and poloxamer 188; and 
 wherein the alginate polymer solution further comprises a cell suspension comprising a plurality of cells.